Through studying the flow resistance coefficient of the control valve,it is found that the flow resistance coefficient of the control valve is mainly affected by the structure of the valve body and the valve core.Combining the equal percentage flow regulation characteristics of the regulating valve with the structural characteristics,the formula for solving the flow area under each opening of the regulating valve was derived,and the design method of plunger regulating valve spool mould line was proposed by an equivalent area curve method based on the calculation result of the formula.The results show:the spool designed by the method makes the flow regulation characteristics obtained by the simulation of the control valve highly consistent with the ideal flow regulation characteristics.This method has high accuracy and reliability,it reduces the workload of the traditional spool design that requires multiple test corrections to a certain extent.